In the paper we present a framework for the secure end-to-end delivery of messages in distributed messaging infrastructures based on the publish/subscribe paradigm. The framework enables authorized publishing and consumption of messages. Brokers, which constitute individual nodes within the messaging infrastructure, also ensure that the dissemination of content is enabled only for authorized entities. The framework includes strategies to cope with attack scenarios such as denial of service attacks and replay attacks. Finally, we include experimental results from our implementation of the framework outlined in this paper.

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We discuss the development and application of Web-service-based geographical information system (GIS) Grids. Following the WS-I+ approach of building Grids on Web service standards, we have developed data Grid components for archival and real-time data, map generating services that can be used to build user interfaces, information services for storing both stateless and stateful metadata, and service orchestration and management tools. Our goal is to support dynamically assembled Grid service collections that combine both GIS services with more traditional Grid capabilities such as file transfer and remote code execution. We are applying these tools to problems in earthquake modeling and forecasting, but we are attempting to build general purpose tools by using and extending appropriate standards.

Grid application frameworks have increasingly aligned themselves with the developments in Web Services. Web Services are currently the most popular infrastructure based on Service Oriented Architecture (SOA) paradigm. There are three core areas within the SOA framework: a set of capabilities that are remotely accessible, communications using messages, and metadata pertaining to the aforementioned capabilities. In this paper, we focus on issues related to the messaging substrate hosting these services; we base these discussions on the NaradaBrokering system. We outline strategies to leverage capabilities available within the substrate without the need to make any changes to the service implementations themselves. We also identify the set of services needed to build Grids of Grids. Finally, we discuss another technology, HPSearch, which facilitates the administration of the substrate and the deployment of applications via a scripting interface. These issues have direct relevance to scientific Grid applications, which need to go beyond remote procedure calls in client-server interactions to support integrated distributed applications that couple databases, high performance computing codes, and visualization codes.

Abstract